But different people are accepting of different tastes and even those change with age, what people accept as nice smelling/tasting food can be quite subjective because the very same smell can be overpowering to some while appealing to others.

How to calibrate a sensor for something like that on a per user basis? I don't know, but apparently it's possible because "electronic noses" do exist but are mostly used in laboratory settings, probably on account of their price.

There's also a reason why we still use pigs and dogs for work that require good smelling senses, like search&rescue or truffle foraging. Training these animals is very expensive, but it still seems to be the cheaper option compared to building "smellobots", so I doubt smelling sensor are far enough along to be put into a ton of kitchen bots at small cost.